A fin-field effect transistor (FinFET) can be used for reducing a short channel effect. Silicon-germanium channel regions have been used to enhance the mobility of carriers. However, a silicon-germanium channel has a band gap less than that of a silicon channel and, thus, a leakage current in an off-state may increase due to band to band tunneling (BTBT). Improved methods of reducing a leakage current in an off-state while maintaining a high mobility of carriers may be desired.